Brave shields are based on ubo, but are patched directly into chromium so they should be immune against v3. Still going to stay on Firefox, but brave is a decent backup option. https://brave.com/blog/brave-shields-manifest-v3/

I really don’t understand people that prefer Google over Mozilla. Firefox works like a charm and Google already knows enough about us IMHO.

Firefox objectively has poor responsiveness in some apps, hence why some "works only in chrome" banners are justified. Can't quite put my finger of it, but it got a lot worse somewhere between quantum and heartbleed(but not because of it, I checked), and it never recovered. In my own projects that were time-sensitive, like 3d games and music apps, I couldn't find the source of it, but found that while some approaches led to major performance hit on firefox, others majorly hit chromium, and vice versa, and it was all about juggling to finding an approach that doesn't hit either as hard. But in some cases there were none and so I had to choose. Obviously the browser engine with a higher market share wins. And because of that, to be on par with Chrome, Firefox not only has to be better, it has to be not worse in all cases, which is a rather tough challenge.